Semiconductor integrated circuit with TSV bumps

ABSTRACT

A semiconductor integrated circuit is provided. In the semiconductor integrated circuit, each of ESD protection circuitries is disposed between two of TSV bumps arrayed in a matrix, the two being arranged adjacent to each other. First main power lines are disposed to overlap P-channel ESD protection elements. Second main power lines are disposed to overlap N-channel ESD protection elements. The first and second main power lines are arranged orthogonally to each other.

INCORPORATION BY REFERENCE

This application claims the benefit of priority based on Japanese PatentApplication No. 2012-260185, filed on Nov. 28, 2013, and Japanese PatentApplication No. 2013-218410, filed on Oct. 21, 2013. The disclosures ofJapanese Patent Applications Nos. 2012-260185 and 2013-218410 areincorporated herein by reference.

BACKGROUND ART

The present invention is related to a semiconductor integrated circuitand suitably used for a semiconductor integrated circuit with a layoutbased on a TSV bump technique, in which a plurality of TSV (throughsilicon via) bumps arrayed in a matrix, such as a wide I/O(input/output) and a HBM (high bandwidth memory).

Recently, there exists an increasing demand of mobile DRAMs (dynamicrandom access memories) with a lower power consumption and a higher datatransmission rate in applications to smart phones, slate type or tablettype personal computers (PCs) and the like. There are two generallyknown techniques for increasing the data transmission rate of a memory;one is to increase the operation frequency of the input/output bus andthe other is to enlarge the bit width of the input/output bus. The useof the technique of increasing the data transmission rate by increasingthe operation frequency, such as LPDDR (low power double data rate) typememories, however, may result in an increase in the power consumption.

A technique called wide I/O is known in the art in connection withLPDDR. In a wide I/O, the total number of input/output pins is increasedto increase the width of the input/output bus; this allows keeping ahigh data transmission rate and reducing power consumption, with a loweroperation frequency.

An implementation of a wide I/O technique basically requires siliconchip stacking in which circuits are electrically connected each othervia TSVs formed through the stacked semiconductor substrates.Accordingly, the positions of input/output pads of a DRAM and a SOC(system on chip) device should be aligned. The arrangement ofinput/output pads in the wide I/O region is standardized by JEDEC (JointElectron Devices Engineering Council).

FIG. 1A is an example of the structure of a stack of serially-connectedsilicon chips. In the structure example shown in FIG. 1A, a plurality ofDRAM silicon chips each having an elemental device 351 and aninterconnection layer 352 are stacked. These silicon chips are connectedvia micro bumps 351 and TSVs 356. There silicon chips are electricallyconnected to an interconnection layer 354 of an SoC device 353 viavia-contacts provided through the SoC device 353. The SoC device 353 ismounted on a package substrate 355 which have bumps 363.

As disclosed in non-patent literature 1 (the JEDEC standard, entitled“wide I/O single data rate”, JESD 229, December 2011), JEDEC (or SolidState Technology Association) has standardized the arrangementcoordinates and definitions of the input/output pads of the wide I/Oregion connected to an SoC device or a DRAM. FIG. 1B is a plan viewillustrating an example of the structure in which I/O buffers arelocated under bumps arranged in a TSV array region. FIG. 1B illustratesa region in which TSV bumps and buffers (denoted by numeral 901) arearranged in a rectangular matrix as well as a region in which ESDprotection circuitries 902 and a PLL circuitry 903 are arranged.

The arrangement of TSV bumps and I/O buffers connected to input/outputpads standardized by JEDEC is disclosed as a SoC floor plan of a wideI/O in non-patent literature 2 (proceedings of Mobile Memory Forum:LPDDR3 and Wide I/O, which is held on Jul. 24, 2011 in Korea).

In connection with non-patent literatures 1 and 2, a structure is knownin which a main VDD power line is connected to a TSV bump via aP-channel ESD (electrostatic discharge) protection element and a mainVSS power line is connected to the TSV bump via an N-channel ESDprotection element.

Patent literature 1 (JP 2010-135391 A) discloses a structure in whichP-channel and N-channel ESD protection elements are disposed at adjacenttwo sides of a TSV bump and a pre-amplifier circuitry of an I/O bufferis disposed between the P-channel and N-channel ESD protection elements.

SUMMARY OF THE INVENTION

In one embodiment, two ESD protection elements respectively connected toadjacent two TSV bumps are disposed between the two TSV bumps. Thiseffectively reduces the power consumption of the wide I/O region andalso reduces the chip size.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages and features of the presentinvention will be more apparent from the following description ofcertain preferred embodiments taken in conjunction with the accompanyingdrawings, in which:

FIG. 1A is a sectional view illustrating an example of the structure ofa stack of multiple silicon chips;

FIG. 1B is a plan view illustrating a structure in which I/O buffers arelocated under bumps in a TSV array region;

FIG. 1C is a plan view illustrating an example of the layout structureof a conventional semiconductor integrated circuit;

FIG. 2A is a partial plan view illustrating details of the example ofthe layout structure of the conventional semiconductor integratedcircuit;

FIG. 2B is a partial plan view illustrating details of an example of thelayout structure of a conventional semiconductor integrated circuit witha multi-finger gate structure;

FIG. 3A is a sectional view illustrating an example of the cross sectionstructure of the conventional semiconductor integrated circuit onsection A-A illustrated in FIG. 2A;

FIG. 3B is an equivalent circuit diagram indicating discharging paths inthe case when ESD-protection and driver elements are disposed in anoutput buffer;

FIG. 3C is an equivalent circuit diagram indicating discharging paths inthe case when ESD protection elements are disposed in an input buffer;

FIG. 4 is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit according to a first embodiment;

FIG. 5A is a plan view illustrating an exemplary structure of a unitstructure set which forms the layout structure of the semiconductorintegrated circuit in the first embodiment;

FIG. 5B is a plan view illustrating an exemplary structure of each unitstructure of a unit structure set in the first embodiment;

FIG. 6 is a sectional view illustrating an exemplary structure of thesemiconductor integrated circuit on section B-B illustrated in FIG. 5B,in the first embodiment;

FIG. 7 is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit according to a second embodiment;

FIG. 8A is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit according to a third embodiment;

FIG. 8B is a plan view illustrating an exemplary structure of a unitstructure set which forms the layout structure of the semiconductorintegrated circuit in the third embodiment;

FIG. 8C is a plan view illustrating an exemplary structure of each unitstructure of the unit structure set in the third embodiment;

FIG. 9A is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit according to a fourth embodiment;

FIG. 9B is a plan view illustrating an exemplary structure of a unitstructure set which forms the layout structure of the semiconductorintegrated circuit in the fourth embodiment;

FIG. 9C is a plan view illustrating an exemplary structure of each unitstructure of the unit structure set in the fourth embodiment;

FIG. 10A is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit according to a fifth embodiment;

FIG. 10B is a plan view illustrating an exemplary structure of a unitstructure set which forms the layout structure of the semiconductorintegrated circuit in the fifth embodiment;

FIG. 10C is a plan view illustrating an exemplary structure of each unitstructure of the unit structure set in the fifth embodiment;

FIG. 11A is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit according to a sixth embodiment;

FIG. 11B is a plan view illustrating an exemplary structure of a unitstructure set which forms the layout structure of the semiconductorintegrated circuit in the sixth embodiment; and

FIG. 11C is a plan view illustrating an exemplary structure of each unitstructure of the unit structure set in the sixth embodiment;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments will be now described herein with reference to the attacheddrawings. For fully explaining an objective of the present invention, adescription is first given of a conventional semiconductor integratedcircuit.

FIG. 1C is a plan view illustrating an exemplary layout structure of aconventional semiconductor integrated circuit. A description is givenbelow of respective elements of the layout structure illustrated in FIG.1C. The layout structure includes a plurality of unit structures 10,main VSS power lines 101 and main VDD power lines 102. Each unitstructure 10 includes an ESD protection circuitry 1, anarbitrarily-designed circuitry 2, a TSV bump 3 and a TSV interconnection4. The unit structures 10 are arrayed in rows and columns. A set of fourunit structures 10 arrayed in two rows and two columns are referred toas unit structure set 301.

FIG. 2A is a partial plan view illustrating details of the exemplarylayout structure of the conventional semiconductor integrated circuit.FIG. 2A illustrates a part of the layout structure illustrated in FIG.1, that is, the structure of one unit structure set 301. In thefollowing, a description is given of unit structures of the unitstructure set 301 illustrated in FIG. 2A. As described above, each unitstructure set 301 includes four unit structures 10. As described above,each of the four unit structures 10 includes an ESD protection circuitry1, an arbitrarily-designed circuitry 2, a TSV bump 3 and a TSVinterconnection 4. The ESD protection circuitry 1 includes a P-channelESD protection element 21 and an N-channel ESD protection element 31.The P-channel ESD protection element 21 includes a drain interconnection22, a source interconnection 23, through-hole contacts 25 (denoted bywhile squares) and through-hole vias 26 (denoted by black squares). TheN-channel ESD protection element 31 includes a drain interconnection 32,a source interconnection 33, through-hole contacts 35 (denoted by whilesquares) and through-hole vias 36 (denoted by black squares).

The connections among the elements illustrated in FIG. 2A are asfollows: The drain interconnections 22 and 32 are connected to the TSVbump 3. The source interconnection 23 is connected to a main VDD powerline 102 by the through-hole vias 26. The source interconnection 33 isconnected to a main VSS power line 101 by the through-hole vias 36.

FIG. 2B is a partial plan view illustrating details of an exemplarylayout structure of a conventional semiconductor integrated circuit witha multi-finger gate structure. The layout structure illustrated in FIG.2B is almost similar to that illustrated in FIG. 2A; the difference isthat the P-channel and N-channel ESD protection elements 21 and 31 eachhave a multi-finger gate structure. The structures of other portions ofthe device illustrated in FIG. 2B are identical to those illustrated inFIG. 2A, and no further description is given of FIG. 2B.

FIG. 3A is a sectional view illustrating the cross section structure ofthe conventional semiconductor integrated circuit on section A-Aillustrated in FIG. 2A. Illustrated in FIG. 3A are an N-well 104, a TSVbump 3, a TSV interconnection 4, a P-channel ESD protection element 21,a through-hole contacts 25, a source interconnection 23, a through-holevias 26, a main VDD power line 102, and a main VSS power line 101.

It should be noted that, although only the P-channel ESD protectionelement 21 is described in the following, the N-channel ESD protectionelement 31 is understood as having a similar structure.

Referring to FIG. 3A, the P-channel ESD protection 21 includes a firstportion 202 and a second portion 203. Here, the portion 202 is a portionlocated just under the main VDD line 102 of the P-channel ESD protectionelement 21. Similarly, the portion 203 is a portion located just underthe main VSS line 101 of the P-channel ESD protection element 21. Itshould be noted that the P-channel ESD protection element 21additionally includes a third portion 204 as described later.

The connections among the elements shown in FIG. 3A are as follows: TheTSV bump 3 is formed through the N-well 104 and connected to the TSVinterconnection 4. The P-channel ESD protection element 21 is formed inthe surface portion of the N-well 104. The source interconnection 23 isformed in an interconnection layer positioned over the P-channel ESDprotection element 21. The P-channel ESD protection element 21 and thesource interconnection 23 are connected to each other via thethrough-hole contacts 25 provided therebetween. The main VDD power line102 is formed in an interconnection layer positioned over the sourceinterconnection 23. The source interconnection 23 is connected to themain VDD power line 102 via the through-hole vias 26.

The two arrows illustrated in FIG. 3A indicate first and second ESDdischarging paths 200 and 201, which reach the main VDD power line 102from the P channel ESD protection element 21.

The first ESD discharging path 200 passes through the through-holecontacts 25 positioned just above the first portion 202, penetrates thesource interconnection 23, and reaches the main VDD power line 102,which is positioned in the upmost interconnection layer, via thethrough-hole vias 26.

The second ESD discharging path 201 passes through the through-holecontacts 25 positioned just above the second portion 203, passes throughthe source interconnection 23 in the horizontal direction, and reachesthe main VDD power line 102, which is positioned in the upmostinterconnection layer, via the through-hole vias 26.

FIG. 3B is an equivalent circuit diagram indicating the dischargingpaths in the case when ESD protection and driver elements are providedin an output buffer. Illustrated in the equivalent circuit diagram ofFIG. 3 are a TSV bump 250, a P-channel ESD protection and driver element2511, an N-channel ESD protection and driver element 2521, a VDD powersupply 261, a VSS power supply 262 and a pre-driver circuit 2531. TheVDD power supply 261 is connected to the source of the P-channel ESDprotection and driver element 2511. The drains of the P-channel andN-channel ESD protection and driver elements 2511 and 2521 are commonlyconnected to the TSV bump 250. Two outputs of the pre-driver circuit2531 are connected to the gates of the P-channel and N-channel ESDprotection and driver elements 2511 and 2521, respectively. The VSSpower supply 262 is connected to the source of the N-channel ESDprotection and driver element 2521. Two discharging paths 271 and 272are illustrated in the equivalent circuit diagram of FIG. 3B. The firstdischarging path 271 reaches the VDD power supply 261 from the TSV bump250 via the drain and source of the P-channel ESD protection and driverelement 2511. The second discharging path 271 reaches the TSV bump 250from VSS power supply 262 via the source and drain of the N-channel ESDprotection and driver element 2521.

FIG. 3C is an equivalent circuit diagram indicating discharging paths inthe case when ESD protection elements are provided in an input buffer.Illustrated in the equivalent circuit diagram of FIG. 3C are a TSV bump250, a P-channel ESD protection element 251, an N-channel ESD protectionelement 252, a VDD power supply 261, a VSS power supply 262 and an inputcircuit 253. The VDD power supply 261 is connected to the source andgate of the P-channel ESD protection element 251. The TSV bump 250 isconnected to the drains of the P-channel and N-channel ESD protectionelements 251 and 252 and an input of the input circuit 253. The VSSpower supply 262 is connected to the source and gate of the N-channelESD protection element 252. Two discharging paths 271 and 272 areillustrated in the equivalent circuit diagram of FIG. 3C. The firstdischarging path 271 reaches the VDD power supply 261 from the TSV bump250 via the drain and source of the P-channel ESD protection element251. The second discharging path 272 reaches the TSV bump 250 from theVSS power supply 262 via the source and drain of the N-channel ESDprotection element 252.

Note that the resistances of the first and second ESD discharging path200 and 201, which are shown in FIG. 3A, are different from each other.The major components of the overall resistance of the first ESDdischarging path 200 include the resistances of the through-holecontacts 25 and the through-hole vias 26. In general, a large number ofthrough-hole contacts 25 and through-hole vias 26 are provided on theP-channel ESD protection element 21 and the source interconnection 23,respectively. Accordingly, the total resistances of the through-holecontacts 25 and through-hole vias 26 ranges from 0.1 to 0.2Ω in general.

The overall resistance of the second ESD discharging path 201, on theother hand, includes the resistance of the source interconnection 23 inaddition to the overall resistance of the first ESD discharging path200. The resistance of the source interconnection 23, which may dependon the layout of the semiconductor integrated circuit and themanufacture process, ranges from 0.1 to 1.0 Ω.

Considered in the following is the case in which the ratio of theresistances of the first and second ESD discharging paths 200 and 201 is1:2 and the areas of the first and second portions 202 and 203 of theP-channel ESD protection element 21 are the same. Furthermore, the ESDdischarging current necessary for satisfying the requirement of the ESDwithstand voltage and the maximum ESD discharging ability of theP-channel ESD protection element 21 are both assumed as 3I amperes,where I is an arbitrary current level.

In such a case, a current of 2I amperes or below flows through the firstESD discharging path 200 and a current of 1I amperes or below flowsthrough the second ESD discharging path 201, in accordance with theabove-described resistance ratio. The maximum ESD discharging abilitiesof the first and second portions 202 and 203 of the P-channel ESDprotection element 21 are, however, both 1.5I amperes. Accordingly, theESC discharging ability of the first ESD discharging path 200 isrestricted to 1.5I amperes, which is the maximum ESD discharging abilityof the first portion 202. Similarly, the ESC discharging ability of thesecond ESD discharging path 201 is restricted to 1I amperes, which isthe maximum ESD discharging ability of the source interconnection 23. Asa result, the overall ESD discharging ability of the P-channel ESDprotection element 21 is restricted to 2.5I amperes.

In order to allow flowing a current of 3I amperes, which is the originalESD discharging ability, through the P-channel ESD protection element21, it is necessary to enlarge the size of the first portion 202, whichis connected to the first ESD discharging path 200, of the P-channel ESDprotection element 21 so that a current of 2I amperes can flow throughthe first portion 202. In the example of FIG. 3A, a third portion 204 isadded to the P-channel ESD protection element 21.

The increase in the size of the P-channel ESD protection element 21,however, also increases the parasitic capacitances between the sourceinterconnection 23 and the silicon substrate and between the draininterconnection 22 and the silicon substrate. In addition, the increasein the size of the P-channel ESD protection element 21 causes anincrease in the power consumption of TSV wide I/O region due to anincrease in the subthreshold leakage current.

Also, only ESD protection elements with a limited size can be arrangedin such a narrow region as the standardized wide I/O region. Thisnecessitates preparing an efficient layout structure so thatsize-limited ESD protection elements can fully exert the dischargingability.

In the following, a description is given of a semiconductor integratedcircuit according to a first embodiment, in which the above-describedproblem is solved.

First Embodiment

FIG. 4 is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit according to the first embodiment. Inthe following, a description is given of elements of the layoutstructure illustrated in FIG. 4. This layout structure is formed withina TSV array region 500 and includes a plurality of unit structure sets402, main VSS power lines (first main power lines) 411 and main VDDpower lines (second main power lines) 412. The voltage polarities of thefirst and second main power lines may be interchanged. In contrast tothe conventional layout structure illustrated in FIG. 1, there is anundivided region 501, in which no unit structure sets 402 are formed,within the TSV array region 500 in the layout structure of the presentembodiment.

FIG. 5A is a plan view illustrating an exemplary structure of each unitstructure set which forms the layout structure of the semiconductorintegrated circuit according to the first embodiment. In the following,a description is given below of elements of each unit structure set 402illustrated FIG. 5A. Each unit structure set 402 includes first tofourth TSV bumps 403A to 403D, first to fourth TSV interconnections 404Ato 404D, first to fourth P-channel ESD protection elements 421A to 421D,first to fourth N-channel ESD protection elements 431A to 431D and firstto fourth arbitrarily-designed circuitries 420A to 420D. In oneembodiment, each of the P-channel ESD protection elements 421A to 421Dmay include a P-channel MOS transistor which provides ESD protectionbased on the snapback action of the parasitic bipolar transistor.Similarly, each of the N-channel ESD protection elements 431A to 431Dmay include an N-channel MOS transistor which provides ESD protectionbased on the snapback action of the parasitic bipolar transistor.

Each unit structure set 402 can be understood as including first tofourth unit structures. A first unit structure, denoted by numeral 400A,includes the first TSV bump 403A, the first TSV interconnection 404A,the first P-channel ESD protection element 421A, the first N-channel ESDprotection element 431A, the first arbitrarily-designed circuitry 420A.The similar goes for the second to four unit structures.

In the following, a description is given of the connections among theelements in each unit structure set 402 illustrated in FIG. 5A. Thefirst to fourth TSV bumps 403A to 403D included in first unit structure400A are respectively disposed at the four corners of the square asdefined in the standard. The first to fourth TSV interconnections 404Ato 404D are formed around the first to fourth TSV bumps 403A to 403D.

The first TSV bump 403A and the fourth TSV bump 403D are arrayedadjacent to each other in a first direction, that is, the horizontaldirection in FIG. 5A. Similarly, the second TSV bump 403B and the third403D are arrayed adjacent to each other in the first direction. Incontrast, the first TSV bump 403A and the second TSV bump 403B arearrayed adjacent to each other in a second direction orthogonal to thefirst direction, that is, the vertical direction in FIG. 5A. Similarly,the third TSV bump 403C and the fourth TSV bump 403D are arrayedadjacent to each other in the second direction.

The first and second P-channel ESD protection elements 421A and 421B aredisposed between the first TSV bump 403A and the second TSV bump 403B.The drain interconnection 427A connected to the P-type drain region ofthe first P-channel ESD protection element 421A is connected to thefirst TSV bump 403A via the first TSV interconnection 404A. Theconnecting part of the drain interconnection 427A and the first TSVinterconnection 404A may be collectively understood as aninterconnection portion described later. The drain interconnection 427Bconnected to the P-type drain region of the second P-channel ESDprotection element 421B is connected to the second TSV bump 403B via thesecond TSV interconnection 404B. The connecting part of the draininterconnection 427B and the second TSV interconnection 404B may becollectively understood as an interconnection portion described later.

The third and fourth P-channel ESD protection elements 421C and 421D aredisposed between the third TSV bump 403C and the fourth TSV bump 403D.The drain interconnection 427C connected to the P-type drain region ofthe third P-channel ESD protection element 421C is connected to thethird TSV bump 403C via the third TSV interconnection 404C. Theconnecting part of the drain interconnection 427C and the third TSVinterconnection 404C may be collectively understood as aninterconnection portion described later. The drain interconnection 427Dconnected to the P-type drain region of the fourth P-channel ESDprotection element 421D is connected to the fourth TSV bump 403D via thefourth TSV interconnection 404D. The connecting part of the draininterconnection 427D and the fourth TSV interconnection 404D may becollectively understood as an interconnection portion described later.

The first and fourth N-channel ESD protection elements 431A and 431D aredisposed between the first TSV bump 403A and the fourth TSV bump 403D.The drain interconnection 437A connected to the N-type drain region ofthe first N-channel ESD protection element 431A is connected to thefirst TSV bump 403A via the first TSV interconnection 404A. Theconnecting part of the drain interconnection 437A and the first TSVinterconnection 404A may be understood as an interconnection portion.The drain interconnection 437D connected to the N-type drain region ofthe fourth N-channel ESD protection element 431D is connected to thefourth TSV bump 403D via the fourth TSV interconnection 404D. Theconnecting part of the drain interconnection 437D and the fourth TSVinterconnection 404D may be understood as an interconnection portion.

The second and third N-channel ESD protection elements 431B and 431C aredisposed between the second TSV bump 403B and the third TSV bump 403C.The drain interconnection 437B connected to the N-type drain region ofthe second N-channel ESD protection element 431B is connected to thesecond TSV bump 403B via the second TSV interconnection 404B. Theconnecting part of the drain interconnection 437B and the second TSVinterconnection 404B may be understood as an interconnection portiondescribed below. The drain interconnection 437C connected to the N-typedrain region of the third N-channel ESD protection element 431C isconnected to the third TSV bump 403B via the third TSV interconnection404B. The connecting part of the drain interconnection 437C and thethird TSV interconnection 404C may be understood as an interconnectionportion described below.

The first to fourth arbitrarily-designed circuitries 420A to 420D arearranged at the center portion of the unit structure set 402. In otherwords, the first to fourth arbitrarily-designed circuitries 420A to 420Dare arranged in a region surrounded by the first to fourth TSV bumps403A to 403D, the first to fourth TSV interconnections 404A to 404D, thefirst to fourth P-channel ESD protection elements 421A to 421D and thefirst to fourth N-channel ESD protection elements 431A to 431D. Thefirst to fourth arbitrarily-designed circuitries 420A to 420D arerespectively disposed in the four sub-regions defined by dividing thisregion. Four I/O buffer circuits connected to the first to fourth TSVbumps 403A to 403D, respectively, may be arranged in the first to fourtharbitrarily-designed circuitries 420A to 420D, respectively.

Although the four unit structures included in the unit structure set 402shown in FIG. 5A are arranged symmetrically in view of easy circuitdesign and the like, this arrangement is merely one example; thearrangements of the four unit structures may be modified. Morespecifically, the positions of the first and second P-channel ESDprotection elements 421A and 421B, which are arrayed adjacent to eachother, may be interchanged. Similarly, the positions of the first andfourth N-channel ESD protection elements 431A and 431D, which arearrayed adjacent to each other, may be interchanged. The same goes forother combinations of P-channel ESD protection elements arrayed adjacentto each other and other combinations of N-channel ESD protectionelements arrayed adjacent to each other. The positions of ESD protectionelements may be interchanged as long as two requirements are satisfied:one is that each TSV bump is connected to both of P-channel andN-channel ESD protection elements and the other is that each ESDprotection element is disposed at a position at which the ESD protectionelement is connectable to the main power line corresponding to itsconductivity type.

Furthermore, the positions of the first to fourth arbitrarily-designedcircuitries 420A to 420D shown in FIG. 5A may be interchanged. Moreessentially, the shapes or the ratio of the areas of the first to fourtharbitrarily-designed circuitries 420A to 420D may be also freelymodified.

FIG. 5B is a plan view illustrating an exemplary structure of each unitstructure which forms the layout structure of the semiconductorintegrated circuit according to the first embodiment. FIG. 5B, which isa partial plan view selectively illustrating the first unit structure404A out of the four units structures included in the unit structure set402 illustrated in FIG. 5A, illustrates details of the structures of thefirst P-channel ESD protection element 421A and the first N-channel ESDprotection element 431A.

In the following, a description is given of elements of the unitstructure 400A illustrated in FIG. 5B. The unit structure 400A includesthe TSV bump 403A, the TSV interconnection 404A, the P-channel ESDprotection element 421A, the N-channel ESD protection element 431A andthe first arbitrarily-designed circuitry 420A.

The P-channel ESD protection element 421A includes a sourceinterconnection 423A, a group of through-hole contacts 425A (denoted bywhile squares) and a group of through-hole vias 426A (denoted by blacksquares). The N-channel ESD protection element 431A includes a sourceinterconnection 433A, a group of through-hole contacts 435A (denoted bywhile squares) and a group of through-hole vias 436A (denoted by blacksquares).

FIG. 6 is a sectional view illustrating an exemplary cross sectionstructure of the semiconductor integrated circuit according to the firstembodiment on section B-B illustrated in FIG. 6. In the following, adescription is given of elements illustrated in the sectional view ofFIG. 6. Illustrated in the sectional view of FIG. 6 are a first TSV bump403A, a first TSV interconnection 404A, an N-well 414, a first P-channelESD protection element 421A, a group of through-hole contacts 4251A, asource interconnection 423A, a group of through-hole vias 426A and amain VDD power line 412. First and second ESD discharging paths 405 and406 are also illustrated in FIG. 6.

In the following, a description is given of the connections among theelements illustrated in the sectional view of FIG. 6. The first TSV bump403A penetrates the N-well 414 at one end, and connected to the firstTSV interconnection 404A at the other end. The first P-channel ESDprotection element 421A is formed in the surface portion of the N-well414. The source interconnection 423A is formed in an upperinterconnection layer over the first P-channel ESD protection element421A and connected to the first P-channel ESD protection element 421Avia the group of through-hole contacts 4251A. The main VDD power line412 is formed in an interconnection layer over the sourceinterconnection 423A, and connected to the source interconnection 423Avia the group of through-hole vias 426A. The group of through-holecontacts 4251A are formed under the group of through-hole vias 426A.

The structure of the first N-channel ESD protection element 431A issimilar to the first P-channel ESD protection element 421A, except forthat the conductivity type of the well and the polarity of the mainpower line are inverted.

In the following, a description is given of the first and second ESDdischarging paths 405 and 406. As shown in FIG. 6, both of the first andsecond ESD discharging paths 405 and 406 reaches the main VDD power line412 from the first P-channel ESD protection element 421A via thethrough-hole contacts 4251A and the through-hole vias 426A in thevertical direction. In contrast to the conventional structureillustrated in FIG. 3A, the first and second ESD discharging paths 405and 406 have the substantially same resistance; none of the first andsecond ESD discharging paths 405 and 406 is routed via the sourceinterconnection 423 in the horizontal direction.

Accordingly, the structure of the first embodiment illustrated in FIG. 6does not require a portion corresponding to the third portion 204illustrated in FIG. 3A, which is required by the conventional technique.As a result, the first embodiment enables reducing the size of the ESDprotection elements, reducing the parasitic capacitances between thesources of the ESD protection elements and the silicon substrate andthose between the drains of the ESD protection elements and the siliconsubstrate, reducing the leakage current, and saving the powerconsumption in the wide I/O region.

Also, in the first embodiment, four logic circuits respectivelyconnected to the four TSV bumps 403A to 403D can be arranged in the fourarbitrarily-designed circuitries 420A to 420D illustrated in FIG. 5A.This allows reducing the circuit size by the area of the region 501without affecting easiness of routing among the ESD protection elementsand logic circuit elements included in the I/O buffers. Accordingly, thestructure of the first embodiment allows effectively reducing the chipsize.

It should be noted that, although the above-description of the firstembodiment is based on an assumption that ESD protection elements, eachof which provides ESD protection based on the snapback action of theparasitic bipolar transistor of the MOS transistor, are used, the sameadvantageous effect can be obtained in the case when other ESDprotection elements, such as ESD protection diodes, are used.

Second Embodiment

FIG. 7 is a partial plan view illustrating an exemplary layout structureof a semiconductor integrated circuit according to the first embodiment.The layout structure illustrated in FIG. 7 is almost similar to thelayout structure of the first embodiment illustrated in FIG. 4; thedifference is that first, second and third arbitrarily-designedcircuitries 415, 416 and 417 are added to the layout structureillustrated in FIG. 7. The first to third arbitrarily-designedcircuitries 415 to 417 are disposed between a plurality of unitstructure sets integrated in the semiconductor substrate.

For example, some or all of the first to third arbitrarily-designedcircuitries 415 to 417 may incorporate a capacitor element connected toa main VDD power line 412 and a main VSS power line 411, which arepositioned in an upper interconnection layer. In this case, variationsin the power supply voltages are reduced on the main VDD power line 412and the VSS power line 411 and the noise immunity is improved.

Also, some or all of the first to third arbitrarily-designed circuitries415 to 417 may incorporate an inter-power supply ESD protection elementconnected to a main VDD power line 412 and a main VSS power line 411,which are positioned in an upper interconnection layer. In this case,the ESD withstand voltages of the main VDD power line 412 and the mainVSS power line 411 are improved.

Furthermore, if capacitance elements and arbitrarily-designedcircuitries such as inter-power supply ESD protection circuits, whichare conventionally arranged around the TSV array region 500, arearranged as the first to third arbitrarily-designed circuits 415 to 417within the TSV array region 500, this effectively reduces the overallchip size of the semiconductor integrated circuit.

Third Embodiment

FIG. 8A is a plan view illustrating an exemplary layout structure of asemiconductor Integrated circuit in a third embodiment. FIG. 8B is aplan view illustrating an exemplary structure of each unit structure setwhich forms the layout structure of the semiconductor integrated circuitin the third embodiment. FIG. 8C is a plan view illustrating anexemplary structure of each unit structure which forms the unitstructure set of the semiconductor integrated circuit in the thirdembodiment.

In the following, a description is given of the layout structureillustrated in FIG. 8A. The layout structure of the third embodiment isalmost similar to that of the first embodiment illustrated in FIG. 4;the difference exists in the structure of each unit structure set asdescribed later.

In the following, a description is given of the structure of the unitstructure set illustrated in FIG. 8B. The structure of the unitstructure set of the third embodiment is obtained by modifying thestructure of the unit structure set of the first embodiment (which isillustrated in FIG. 5A) as follows: First, the area of each of the firstto fourth P-channel ESD protection elements 421A to 421D in the thirdembodiment is larger than that in the first embodiment. Similarly, thearea of each of the first to fourth N-channel ESD protection elements431A to 431D in the third embodiment is larger than that in the firstembodiment. As a result, the area of each of the first to fourtharbitrarily-designed circuitries 420A to 420D in the third embodiment issmaller than that in the first embodiment.

It should be noted that the unit structures 400A to 400D are arranged inrotational symmetry for rotations of 90 degrees, 180 degrees and 270degrees in the exemplary structure illustrated in FIG. 8B.

In the following, a description is given of the unit structureillustrated in FIG. 8C. The unit structure of the third embodiment isobtained by modifying that of the first embodiment (illustrated in FIG.5B) as follows: In this embodiment, the P-channel and N-channel ESDprotection elements 421A and 431A each include a MOS transistor with amulti-finger gate structure; the P-channel and N-channel ESD protectionelements 421A and 431A each include a plurality of gate fingers.

In the exemplary structure illustrated in FIG. 8C, the drain regions ofthe multi-finger gate MOS transistors are extended in the first orsecond direction with respect to the TSV interconnections. Note that thedrain region of each MOS transistor is connected to a TSVinterconnection and a TSV bump via a drain interconnection. As a result,a sufficient ESD discharging ability is obtained for the case when amulti-finger gate structure is used, and the same advantageous effect asthe first embodiment is achieved.

The structure of the remainder of the semiconductor integrated circuitin the third embodiment illustrated in FIGS. 8A to 8C is similar to thatin the first embodiment illustrated in FIGS. 4, 5A and 5B. Therefore, nofurther description of the structure of the remainder of thesemiconductor integrated circuit illustrated in FIGS. 8A to 8C is given.

The operation and advantageous effect of the semiconductor integratedcircuit of the third embodiment are also the same as those of the firstembodiment, except for that the protection ability is enhanced due tothe use of the multi-finger gate structure in each ESD protectionelement. Therefore, no further description is given of the operation andadvantageous effect of the semiconductor integrated circuit of the thirdembodiment.

Fourth Embodiment

FIG. 9A is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit in a fourth embodiment. FIG. 9B is aplan view illustrating an exemplary structure of each unit structure setwhich forms the layout structure of the semiconductor integrated circuitin the fourth embodiment. FIG. 9C is a plan view illustrating anexemplary structure of each unit structure which forms the unitstructure set of the semiconductor integrated circuit in the fourthembodiment.

In the following, a description is given of the layout structureillustrated in FIG. 9A. The layout structure of the fourth embodiment isalmost similar to that of the third embodiment illustrated in FIG. 8A;the difference exists in that the area of the region 501 is reduced inconnection with the increase in the area of each unit structure set asdescribed later.

In the following, a description is given of the structure of the unitstructure set illustrated in FIG. 9B. The structure of the unitstructure set of the fourth embodiment is obtained by modifying thestructure of the unit structure set of the third embodiment (which isillustrated in FIG. 8B) as follows: In the first embodiment, all of theP-channel ESD protection elements 421A to 421D, the N-channel ESDprotection elements 431A to 431D and the arbitrarily-designedcircuitries 420A to 420D are accommodated in the region surrounded bythe four TSV bumps 403A to 403D. In contrast, in the fourth embodiment,some of the P-channel ESD protection elements 421A to 421D, theN-channel ESD protection elements 431A to 431D and thearbitrarily-designed circuitries 420A to 420D are extended to theoutside of the region surrounded by the four TSV bumps 403A to 403D.This results from the increase in the area of each unit structure.Attention should be paid to the fact that the portions outside theregion surrounded by the four TSV bumps 403A to 403D are located in thefirst direction with respect to the region. In other word, the elementsof each unit structure set are not extended to the outside of the regionsurrounded by the four TSV bumps 403A to 403D in the second directionwith respect to the region; this implies that a continuous regionextended in the first direction can be obtained.

In the following, a description is given of each unit structureillustrated in FIG. 9C. The unit structure of the fourth embodiment isobtained by modifying that of the third embodiment (illustrated in FIG.8C) as follows: In the fourth embodiment, the size of the N-channel ESDprotection element 431A is further increased from that in the thirdembodiment. It should be additionally noted that this results in notonly the above-described extension of the elements but also the loss ofthe symmetry in the shapes of the four unit structure included in eachunit structure set. The asymmetry in the shape, however, does notdirectly influence the circuit function.

The structure of the remainder of the semiconductor integrated circuitin the fourth embodiment illustrated in FIGS. 9A to 9C is similar tothat in the third embodiment illustrated in FIGS. 8A to 8C, andtherefore no further description of the structure of the remainder ofthe semiconductor integrated circuit illustrated in FIGS. 8A to 8C isgiven.

The operation and advantageous effect of the semiconductor integratedcircuit of the fourth embodiment are also the same as those of the thirdembodiment, except for that the protection ability is enhanced due tothe increase in the size of the N-channel ESD protection element 431A.Therefore, no further description is given of the operation andadvantageous effect of the semiconductor integrated circuit of thefourth embodiment.

Note that, although FIG. 9C illustrates the structure in which the sizeof the N-channel ESD protection element 431A is increased, thisstructure is merely one example; the size of the P-channel ESDprotection element 421A may be increased instead.

Fifth Embodiment

FIG. 10A is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit in a fifth embodiment. FIG. 10B is aplan view illustrating an exemplary structure of each unit structure setwhich forms the layout structure of the semiconductor integrated circuitin the fifth embodiment. FIG. 10C is a plan view illustrating anexemplary structure of each unit structure which forms the unitstructure set of the semiconductor integrated circuit in the fifthembodiment.

In the following, a description is given of the layout structureillustrated in FIG. 10A. The layout structure of the fifth embodiment isalmost similar to that of the third embodiment illustrated in FIG. 8A;the difference exists in the structure of each unit structure set asdescribed later.

In the following, a description is given of the structure of the unitstructure set illustrated in FIG. 10B. The structure of the unitstructure set of the fifth embodiment is obtained by modifying thestructure of the unit structure set of the third embodiment (which isillustrated in FIG. 8B) as follows: In the fifth embodiment, theP-channel ESD protection elements 421A to 421D and the N-channel ESDprotection elements 431A to 431D are arranged so that the longitudinaldirections (or the gate width directions) of the P-channel ESDprotection elements 421A to 421D and the N-channel ESD protectionelements 431A to 431D are respectively directed along the TSV bumps 403Ato 403D, to which the P-channel ESD protection elements 421A to 421D andthe N-channel ESD protection elements 431A to 431D are respectivelyconnected. In the first to fourth embodiments, as illustrated in FIGS.5B, 8C and 9C, the P-channel ESD protection elements 421A to 421D(especially, the drain interconnections 427A to 427D thereof) aredisposed to extend in the directions outward of the TSV bumps 403A to403D, respectively, from the insides. Similarly, in the first to fourthembodiment, the N-channel ESD protection elements 431A to 431D(especially, the drain interconnections 437A to 437D thereof) aredisposed to extend in the directions outward of the TSV bumps 403A to403D, respectively, from the insides. In contrast, in the fifthembodiment illustrated in FIG. 10B, the P-channel ESD protectionelements 421A to 421D, the drain interconnections 427A to 427D thereof,the N-channel ESD protection elements 431A to 431D and the draininterconnections 437A to 437D thereof are disposed to extend in thedirections perpendicular to the directions outward of the TSV bumps 403Ato 403D, respectively, from the insides.

It should be noted that, in the exemplary structure illustrated in FIG.10B, the unit structures 400A to 400D are arranged in rotationalsymmetry with one another for rotations of 90 degrees, 180 degrees and270 degrees.

In the following, a description is given of each unit structureillustrated in FIG. 10C. The unit structure of the fifth embodiment isobtained by modifying that of the third embodiment (illustrated in FIG.8C) as follows: First, as described above, the P-channel ESD protectionelements 421A to 421D and the N-channel ESD protection elements 431A to431D are arranged so that the longitudinal directions of the P-channelESD protection elements 421A to 421D and the N-channel ESD protectionelements 431A to 431D are respectively directed along the TSV bumps 403Ato 403D, to which the P-channel ESD protection elements 421A to 421D andthe N-channel ESD protection elements 431A to 431D are respectivelyconnected. Furthermore, when each of the P-channel ESD protectionelements 421A to 421D include a multi-finger gate, a plurality of drainsof each of the P-channel ESD protection elements 421A to 421D areconnected to the TSV bumps 403A to 403D in parallel via interconnections428A to 428D. Similarly, when each of the N-channel ESD protectionelements 431A to 431D include a multi-finger gate, a plurality of drainsof each of the N-channel ESD protection elements 431A to 431D areconnected to the TSV bumps 403A to 403D in parallel via interconnections438A to 438D.

In the exemplary structure illustrated in FIG. 10C, it may be necessaryto take further measures to equalize the currents through the drainsconnected to a TSV bump via the same interconnection.

The structure of the remainder of the semiconductor integrated circuitin the fifth embodiment illustrated in FIGS. 10A to 10C is similar tothat in the third embodiment illustrated in FIGS. 8A to 8C. Therefore,no further description of the structure of the remainder of thesemiconductor integrated circuit illustrated in FIGS. 10A to 10C isgiven.

The operation and advantageous effect of the semiconductor integratedcircuit of the fifth embodiment are the same as those of the thirdembodiment. Therefore, no further description is given of the operationand advantageous effect of the semiconductor integrated circuit of thefifth embodiment.

Sixth Embodiment

FIG. 11A is a plan view illustrating an exemplary layout structure of asemiconductor integrated circuit in a sixth embodiment. FIG. 11B is aplan view illustrating an exemplary structure of each unit structure setwhich forms the layout structure of the semiconductor integrated circuitin the sixth embodiment. FIG. 11C is a plan view illustrating anexemplary structure of each unit structure which forms the unitstructure set of the semiconductor integrated circuit in the sixthembodiment.

In the following, a description is given of the layout structureillustrated in FIG. 11A. The layout structure of the sixth embodiment isobtained by modifying the layout structure of the fifth embodiment(which is illustrated in FIG. 10A) as follows: First, for each firstmain power line 411 and each second main power line 412, the width ofthe portion overlapping each ESD protection element is reduced to aboutthe half. Second, power line pairs each including one first power line411 and one second power line 412 are disposed to extend in the firstand second directions, and arranged to overlap ESD protection elements.Furthermore, the shape of each unit structure set is different asdescribed below.

In the following, a description is given of the structure of each unitstructure set illustrated in FIG. 11B. The structure of the unitstructure set of the fifth embodiment is obtained by modifying thestructure of the unit structure set of the fifth embodiment (which isillustrated in FIG. 10B) as follows: The P-channel ESD protectionelements 421A and the N-channel ESD protection elements 431A are arrayedin the same direction with respect to the TSV bump 403A, to which theP-channel ESD protection elements 421A and the N-channel ESD protectionelements 431A are connected. The similar goes for the P-channel ESDprotection elements 421B to 421D and the N-channel ESD protectionelements 431B to 431D. The P-channel ESD protection elements 421B andthe N-channel ESD protection elements 431B are arrayed in the samedirection with respect to the TSV bump 403B, the P-channel ESDprotection elements 421C and the N-channel ESD protection elements 431Care arrayed in the same direction with respect to the TSV bump 403C, andthe P-channel ESD protection elements 421D and the N-channel ESDprotection elements 431D are arrayed in the same direction with respectto the TSV bump 403D.

It should be noted that, in the exemplary example illustrated in FIG.11B, the unit structures 400A to 400D are arranged in rotationalsymmetry with one another for rotations of 90 degrees, 180 degrees and270 degrees.

In the following, a description is given of each unit structureillustrated in FIG. 11C. The unit structure 400A of the sixth embodimentis obtained by modifying that of the fifth embodiment (illustrated inFIG. 10C) as follows: As described above, the P-channel ESD protectionelements 421A and the N-channel ESD protection elements 431A are arrayedin the same direction with respect to the TSV bump 403A, to which theP-channel ESD protection elements 421A and the N-channel ESD protectionelements 431A are connected. In addition, an interconnection 428A whichconnects the P-channel ESD protection element 421A to the TSV bump 403Aand an interconnection 438A which connects the N-channel ESD protectionelement 431A to the TSV bump 403A are connected to each other. Further,as described above, the first main power line 411 and the second mainpower line 412 are extended in parallel with the widths thereof reduceddown to the half. As a result, the P-channel ESD protection element 421Ais connected to the first main power line 411 and the N-channel ESDprotection element 431A is connected to the second main power line 412.

In the exemplary structure illustrated in FIG. 11C, it may be necessaryto take further measures to equalize the currents through the drainsconnected to a TSV bump via the same interconnection.

The structure of the remainder of the semiconductor integrated circuitin the sixth embodiment illustrated in FIGS. 11A to 11C is similar tothat in the fifth embodiment illustrated in FIGS. 10A to 10C. Therefore,no further description of the structure of the remainder of thesemiconductor integrated circuit illustrated in FIGS. 11A to 11C isgiven.

The operation and advantageous effect of the semiconductor integratedcircuit of the sixth embodiment are also the same as those of the fifthembodiment, except for that the protection ability is enhanced due tothe use of the multi-finger gate structure in each ESD protectionelement. Therefore, no further description is given of the operation andadvantageous effect of the semiconductor integrated circuit of the sixthembodiment.

Although embodiments of the present invention are specifically describedin the above, the present invention is not limited to theabove-described embodiments; the present invention may be implementedwith modifications which do not depart from the concept of the presentinvention. It should be noted that the features described in theabove-described embodiment may be arbitrarily combined as long as notechnical inconsistency is raised.

What is claimed is:
 1. A semiconductor integrated circuit, comprising: a first TSV bump; a second TSV bump arranged in a first direction with said first TSV bump; a third TSV bump arranged in a second direction which is perpendicular to said first direction with said first TSV bump; a plurality of I/O buffers coupled to said first, second, and third TSV bumps, respectively; first and second power lines; a first P-channel ESD protection circuit which is supplied a first voltage by said first power line and disposed between said first and second TSV bumps; and a first N-channel ESD protection circuit which is supplied a second voltage by said second power line and disposed between said first and third TSV bumps, wherein said first power line is disposed to overlap said first P-channel ESD protection circuit, wherein said second power line is disposed to overlap said first N-channel ESD protection circuit.
 2. The semiconductor integrated circuit according to claim 1, further comprising: third and fourth power lines; a second P-channel ESD protection circuit which is supplied said first voltage by said third power line and disposed between said first and second TSV bumps; and a second N-channel ESD protection circuit which is supplied said second voltage by said fourth power line and disposed between said first and third TSV bumps. 